Henrik Stenson, who leads the greens-in-regulation stats this week but has been let down by his putting, is tied for fourth at two under.

Asked what his hopes were for the day, the optimistic Swede said: "To make six shots better than Martin . . . something's got to happen at some point and hopefully it can happen to me. I might be a bit far behind but you never know what the last day might bring."

If you wanted an idea of how volatile and challenging scoring is on this Pinehurst stretch, Englishman Danny Willet has 14 birdies in a shade over three-and-a-half rounds. He must be flying, then? Not quite. He's 11 over with two holes to play.

Justin Rose says the responsibilities that come with being defending champion have been surprisingly easy to deal with at Pinehurst.

"I'd love to be a few shots closer to Mr Kaymer but I'm on exactly the same score as I was at this stage last year so who knows? A lot can happen out here on this golf course," says Rose.

"My long game has been good and, if I can clean up around the greens a little better I'll keep my score going in the right direction and steal a good round."

The Englishman is one over par and partners American Kevin Na, teeing off at 19:51 BST.

A number of players enjoying a far more productive day today compared with the suffering and pain they endured during the third round. Ian Poulter (+3 for the tournament) birdies the first to go into the red. Keegan Bradley beats par on the third and moves to one under (+3 for the tournament).

A birdie, too, for Steve Stricker, with the American rewarded on the second, although he follows up with a bogey on the third. What rotten luck.

Graeme McDowell has gone out in 34 and the Northern Irishman has started the back nine brightly thanks to a birdie on the 10th. Three birdies so far for the former champion, making amends for a bogey on the fourth, and he is -2 for the day (+5 for the tournament).

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Given that it is Father's Day, it would be remiss not to mention the one father-son partnership on the Pinehurst fairways.

American journeyman Fran Quinn has his son, Owen, on the bag this week and given that the 15-year-old plays off a handicap of 2.9 he may believe he could do better than his old man, who ended +14 after a closing 73.

Phil Mickelson is under par! The six-time runner-up rattles in a birdie on the fifth - his second birdie of the day - and goes -1. Unfortunately for Lefty, he's +4 for the tournament. The US Open's perennial bridesmaid has been shoved from the top table and placed in the corner. At this rate he won't even catch the bouquet. It happens to us all...

The chasing pack need birdies, but who has been the most prolific when it comes to beating par by a stroke this week?

American Brandt Snedeker has made 12 birdies, hitting half a dozen of them in his opening round. He needs to recapture that sort of form if he is to make up seven shots on Martin Kaymer.

The German, by the way, has also hit 12 birdies from three rounds, while Brendon de Jonge has carded 11.

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John McEnerney, external: If MK plays the way he has since Thurs it's his, the chasing group have to play like MK played in the first 2 rounds! It's a big ask!

That hole in one on the par-three ninth sees Zach Johnson out in 35 and he leaps to +7 for the tournament and level par for the day.

His ace on the ninth is the 44th in US Open history and the first since Shawn Stefani sunk one last year.

Hang on, what have we here? Deafening whoops and hollers on the ninth green as Zach Johnson watches the ball gently roll in for a hole in one! A hole in one! Drinks are on Zach this evening. (A large one for us. Thanks).

The jubilant American throws his iron up in the air and then runs towards the gallery to high-five the long line of spectators.

A few players are saying conditions will make scoring easier today and if you're the sort of person who likes to deal in hard, cold facts then there are numbers to back up such claims.

So far, nine players are under par for the day, compared to just two in the entire field by the end of play in round three.

One of those is South African Louis Oosthuizen who is three under for the day but eight over for the tournament.

It is a beautiful cloudless afternoon in Pinehurst and moments ago Rickie Fowler, dressed in his final day orange, gave a thumbs up to the cameras as he made his way to the range. He will be setting off alongside Martin Kaymer at 20: 35 BST.

Rob Meech, external: Would be delighted for Kaymer if he won. Slipped out of the spotlight during a tough spell but class will always come through

Andrew Priestley, external: Every neutral wants to see some excitement, not a victory lap from Martin Kaymer. Here's hoping that Rickie Fowler can go low today

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Pinehurst will forever be associated with the late Payne Stewart, the colourful American who holed a 15ft putt at the last to win the US Open by a stroke from Phil Mickelson in 1999.

It was the first time the tournament had been held on the North Carolina course, and the victory became all the more poignant because seven months later, at the age of 42, he was killed in an air accident.

At the back of the 18th green is a bronze statue of Payne doing a one-legged fist-pump, immortalising his achievements on this course, and on Thursday Rickie Fowler paid tribute to his compatriot by wearing plus-fours and knee-high argyle socks.

"Over the years he became a guy that was such a role model for young players," says Thomas Bjorn. "A brilliant guy to have met and fantastic to be around."

Martin Kaymer would also become the 19th player to win a US Open and a US PGA. Fittingly, another to achieve the feat was the late Payne Stewart, who won the US Open at Pinehurst in 1999 to go with his 1991 US Open win and 1989 PGA title. The last man to collect both titles was Rory McIlroy, who added the 2012 US PGA to his 2011 US Open crown.

Should Kaymer lift the trophy aloft this evening, he would become the eighth start-to-finish winner of the US Open, following Walter Hagen (1914), James Barnes (1921), Ben Hogan (1953), Tony Jacklin (1970), Tiger Woods (2000, 2002) and Rory McIlroy (2011).

Will the German lead from start-to-finish or will someone pop up from the shadows and ruin the 29-year-old's day? Who is the most likely to challenge the leader? Tweet your final-day musings using the hashtag #bbcgolf or tweet 81111. You can also add your comments on BBC Sport's Facebook page.

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7 strokes: Arnold Palmer (72-71-72-65); Cherry Hills, Englewood (Colorado) 1960

6 strokes: Johnny Miller (71-69-76-63); Oakmont (Pennsylvania) 1973

5 strokes: Johnny Farrell (77-74-71-72); Olympia Fields (Illinois) 1928

5 strokes: Byron Nelson (72-73-71-68); West Conshohocken (Pennsylvania) 1939

5 strokes: Lee Janzen (pictured) (73-66-73-68); The Olympic Club (California) 1998

Perhaps the man to rein in Kaymer is Erik Compton, who could turn this US Open into a tale of an inspirational golfer, a man on his third heart, who hauled back a record lead to win his first major.

Compton, along with Rickie Fowler, is Kaymer's nearest challenger and such trivialities like a five-shot lead won't overwhelm the 34-year-old who has undergone two transplants.

Apparently, because of his condition, the American's hands are prone to shake , externalbecause of his system's overproduction of adrenalin but he himself says he is the sort of guy who refuses to quit and he is unlikely to do so when trailing in second spot at a major.

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If Martin Kaymer was to do the unthinkable and relinquish his five-shot advantage, he would become the first man to throw away such a final-day lead since Mike Brady in 1919.

Brady, a nine time winner on the PGA Tour, coughed and spluttered to an 80 on the fourth round and went on to lose a play-off against 11-time major winner Walter Hagen. But such a fall can't happen again, can it?